Page 271 - Handbook of Materials Failure Analysis

4 Conceptual Framework of Specifications for Quality Assurance 267

4 CONCEPTUAL FRAMEWORK OF SPECIFICATIONS
FOR QUALITY ASSURANCE

Returning to the subject of establishing verification specifications, there are plenty of
specifications that have few explanations technically. It is difficult to find articles
that explain to establish specifications; there have been a few research studies about
it. So let’s consider how to anticipate issues in a new product and to configure a series
of verification specifications responding to them, and how to develop specifications
that will identify these issues accurately.
Here is one such methodology. First, select an existing product to be compared
with the new one. All its relevant specifications are listed except the unnecessary
specifications. Second, because inevitably the similar but older product has the
intractable problems to be listed, we must devise new specifications to address these
issues. Ongoing problems indicate that any counter-measures have not resolved the
real cause because of the inadequate analysis. Nonetheless, the original design idea
may be faulty. The existing product would be solved by using precise problem anal-
ysis, and the new product would be handled by identifying and fixing the problem
before releasing the next model. To correct the existing problems in similar products,
it is important to add the verification specifications. Sometimes the potential prob-
lems of the subassemblies manufactured by a new supplier also might be considered.
Third, the newly designed portions—those that differ from the current compara-
ble product—should be listed and the potential issues related to them should be pre-
dicted. Verification specifications need to be devised to address these problems.
Especially, note that all items incorporating new chemical materials should be tested
to item lifetime under new quantitative specifications because a new kind of wear-
out failure could occur near the item lifetime. Moreover, it is very difficult to
computer-simulate and clarify diverse chemical reactions over an item’s lifecycle.
Finally, the new product will also have performance fundamentals unique to it,
which sometimes provide a competitive edge over competitors. Such comparative
advantages in performance fundamentals might be checked with the newly estab-
lished specifications.
A complete set of verification specifications in Figure 11.7 might be summarized
as four types of data: (1) all the verification specifications for the comparable
product(s); (2) specifications to fix existing problems in the comparable product;
(3) specifications that deal with the potential issues in the newly designed portions;
and (4) specifications checking newly incorporated performance features. The
specifications responding to the latter three categories are all established anew.
The purpose of sectioning potential issues in a new product is to check whether
necessary issues have been omitted or not.
All specifications enumerated according to this model would be classified, ini-
tially, into two groups: performance specifications and reliability specifications. If
an issue to be identified is related to material rupture or degradation, especially over